As disclosed, e.g., in U.S. Pat. Nos. 4,482,669 (Seyferth et al.) and 4,771,118 (Takamizawa et al.) and in Zoeckler et al., Journal of Organic Chemistry, Volume 48, pp. 2539-2541 (1983), and Blum et al., Organometallics, Volume 5, No. 10, pp. 2081-2086 (1986), it is known that organosilazanes are useful in the synthesis of organosilazane polymers and that they can be prepared by reacting an organohalosilane with ammonia in an organic solvent at a temperature in the range of 0.degree. C. to -20.degree. C.
It has now been discovered that the molecular weights of polysilazanes synthesized by the polymerization of such organosilazanes are dependent on the molecular weights of the organosilazane precursors as well as on the polymerization time and that the use of a lower molecular weight organosilazane necessitates a longer polymerization time to achieve a desired polysilazane molecular weight. It would therefore be desirable to find a means of increasing the molecular weights of organosilazanes prepared by an ammonolysis reaction.